What I would like:
Mamiya Universal or Super23 with a 100/2.8 lens...let's work through your list:
1. Easily hand held - yes, it's a bit heavy but there are grips and the form factor is not boxy. Zero vibration, handles slow handheld speeds very well.
2. No moving mirror (ala SLR), so kind of leaves TLR and RF, unless there is one I missed - yes, it's a RF
3. 6x6 or larger preferred - yes, there are backs for 6x7, 6x9, switchable 645/6x6/6x9, and [on the Universal only] full-frame Polaroid packfilms
4. Cable release compatible w/ bulb setting - yes
5. Sharp lens - yes, at least half of the lens range, especially the 100/2.8 and the 50mm and 75mm non-retrofocus wideangles, are very sharp
6. f3.5 or faster, f2.8 is preferred (use mostly 100 and 160 speed films) - yes, there's an f2.8 100mm standard lens, and f3.5 90mm and 100mm standard lenses. Longer and shorter lenses are slowish however.
7. Fixed or interchangeable lenses, no problem with either - yes, interchangeble
8. Built in light meter, doesn't need to set exposure, just give me an idea what I need to be at - none!...but everyone's telling you to use a handheld meter anyway
9. Less than $1,000USD - much less
10. The more mechanical the better, I love the fact the Yashica doesn't need batteries. - absolutely 100% mechanical.
11. If possible, some kind of focus confirmation, like a split prism or coupled RF - coupled RF with a very wide baseline. Also several direct and reflex ground-glass viewing options on the focal plane, view-camera style
Now, I know that is a long list, and I am willing to make concessions on some of those if need be (such as 11, 8 and 3). - 8 is the only one in this case
This is used as a walk around camera and travel camera, so size being as small as possible is always a plus. - not really small in use, but breaks down small and flat for transport as it is completely modular
This is for personal stuff, and I have digital gear in addition, so if the camera has quirks, I have no problem working around them. As for focal length, as long as the lens is sharp and decent wide open, I am good in the slightly wide to normal range. - yes, the 100/2.8 fills those requirements. It's equivalent to a 43mm "wide normal" lens on a 35mm camera
So far I have been thinking a fixed lens Fuji RF, maybe a 6x9. - that would be smaller, but the Fuji lens is slower and nothing (lenses, backs, formats, ground-glass and reflex finders, grips) is interchangeable
Hope that helps.
Ray